两种金属-有机钙钛矿材料的负热膨胀性质

通过变温单晶X射线衍射和透射电镜实验对2种金属-有机钙钛矿材料[C(NH2)3][Mn(HCOO)3](1)和[(CH2)3NH2][Mn(HCOO)3](2)进行表征,分析了其晶体结构和晶格常数随温度变化的关系,发现2种材料沿c轴方向都表现出负的热膨胀行为,其效应分别为:αc1=-1.2(1)×10~(-5)K~(-1),αc2=-6.1(11)×10~(-5)K~(-1)。采用一种"铰链"结构模型对这2种框架材料的负热膨胀机理进行了详细解释:温度升高会诱导框架中主体和客体铵基之间的氢键长度及键角发生改变,引起钙钛矿框架结构发生变形,进而导致其沿框架对角线方向(c轴方向)的负热膨胀行为。     

Nonsequential double ionization of diatomic molecules by elliptically polarized laser pulses

Using the classical ensemble method, we investigate nonsequential double ionization （NSDI） of diatomic molecules by elliptically polarized laser pulses. The results show that the ellipticity of the laser field has a strong suppression effect on NSDI probabilities both in parallel and perpendicular alignments. The double ionization （DI） channel is commonly dominated by NSDI, and the NSDI channel changes with ellipticity. As ellipticity increases, more and more NSDIs occur through recollision excitation with subsequent field ionization （RESI）. Moreover, like the case of linear polarization, the two electrons involved in NSDI for perpendicularly aligned molecules are more likely to emit into the opposite hemispheres as compared to the case of parallel alignment. Additionally, this alignment effect increases as ellipticity increases.     

一种车辆模型辅助的MEMS-SINS导航方法

针对城市环境中GNSS因遮挡导致MEMS-SINS精度快速降低的问题,在车辆运动学约束的基础上,结合四通道ABS轮速传感器和方向盘转角信息,提出一种新的适用于陆地车辆的MEMS-SINS导航方法。该方法通过分析车辆转弯和运动约束特性,构建角速度和加速度观测量,从而实现基于模型辅助的MEMS误差在线补偿;其次,ABS轮速信息与非完整约束条件结合可额外增加三维车体速度观测量,进一步维持卫星失效时组合滤波器的量测更新。跑车实验表明,在GNSS信号频繁丢失甚至长时间无法定位时,低精度MEMS惯性器件引起的快速误差积累得到有效抑制,与经典车体约束结合里程计算法相比,航向精度提高约70%,位置、速度精度也有相应的提高,验证了算法的有效性。     

极化蛋白专一性电荷在HIV-1蛋白酶-抑制剂结合自由能预测中的应用

对人类免疫缺陷病毒（HIV-1）蛋白酶-抑制剂复合物分别在AMBER力场及极化专一性蛋白电荷（PPC）下进行10 ns的分子动力学模拟（MD）,并用MM/PBSA方法计算结合自由能.PPC是基于线性标度的量子力学计算的静电势拟合的蛋白质电荷,能够更准确地描述蛋白质所处的静电环境.结果表明：PPC电荷计算的结合自由能比AMBER力场计算的结合自由能更接近实验值.     

Synthesis,Structure, Photoluminescence and Thermal Expansion of a Rare Earth Formate Oxalate Framework

A new lanthanide formate oxalate framework[Eu(C_2O_4)(HCOO)]_n(1)has been synthesized via hydrothermal method and characterized by single-crystal X-ray diffraction(SC-XRD).The framework crystallizes in the orthorhombic Pnma space group,with a=7.0984(4),b=6.6442(3),c=10.6793(6)?,V=503.68(4)?~3,Z=3,C_3HO_6Eu,M_r=285.00 g/mol,D_c=3.7581 g/cm~3,F(000)=520.3796,μ=12.413 mm~(-1),the final R=0.0264 and w R=0.0628 for 797observed reflections with I2σ(I).The photoluminescence(PL)measurements reveal the significant red emission of the framework is dominated by the(~5D_0→~7F_2)electronic transition at614 nm.Further variable-temperature powder X-ray diffraction(VT-PXRD)indicates that framework 1 shows slight negative thermal expansion(NTE)along the a-axis,and positive thermal expansion(PTE)along the b and c axes.     

Improvement of Test of Solar Neutrino Coherent Scattering with Torsion Pendulum

A torsion pendulum containing two sapphire crystals and two lead rings is used to test Weber＇s theory of enhanced solar neutrino coherent scattering. Our experiment gives a null result for the diurnal force with a noise level of 3.8 × 10^-14 N, which is 526 times smaller than the predicted value of Weber＇s theory, and directly rules out Weber＇s theory and the experimental result. This experiment also reveals a test of the weak equivalence principle with η （Al2O3, Pb） （0.8 ± 3.1） × 10^-10 for masses falling toward the Sun.     

氦原子非次序双电离对正交双色场强度比的依赖关系

利用经典系综模型研究了正交双色场中氦原子非次序双电离对双色场强度比的依赖关系.研究表明, 该依赖关系与双色场相对相位φ 有关. φ =0.25π 时,沿长波长激光偏振方向的相关动量谱随强度比的增大从相关模式转变为反相关模式. φ =0.35π, 0.45π 时,相关动量主要分布在第一和第三象限,相关模式几乎不随强度比的变化而变化.对双电离轨迹碰撞时间、碰撞角、碰撞动量的向后分析可以解释上述结果,并显示了正交双色场对非次序双电离中碰撞时间、碰撞角的控制作用.     

Synthesis,Structure, and Magnetic and Luminescent Properties of Rare Earth Coordination Polymers Constructed from Mixed Dicarboxylates

Three unique metal-organic framework coordination polymers, [Eu_2(bptc)(bdc)_2(H_2O)]_n(1), [Gd_2(bptc)(bdc)_2(H_2O)_4]_n(2) and [Dy_2(bptc)(bdc)_2(H_2O)_4]n(3)(1,2-H_2 BDC = 1,2-benzenedicarboylic acid, H_2 bptc = 4,4?-biphenyldicarboxylic acid) were synthesized by mixing two different multi-carboxylic acids with Ln2 O3(Ln = Eu, Gd and Dy) in hydrothermal condition. The three compounds are all three-dimensional and compounds 2 and 3 contain 4.289 × 6.507 ?~2 rectangularshaped one-dimensional open channels along the a direction. Additionally, the magnetic, luminescent and thermogravimetric properties were studied in detail.     

分子双电离对激光偏振性的依赖关系

利用经典系综模型研究了氢分子双电离对激光场椭圆率的依赖性.研究发现,氢分子双电离机制对激光的椭偏性有强烈的依赖关系.随着激光场椭圆率的增加,双电离机制由非次序双电离转变为次序双电离.在大椭圆率情况的次序双电离中,电子关联动量分布随椭圆率的灵敏变化显示了电子出射时间对椭圆率的强烈依赖关系.